Andi Kleen wrote:> On Sun, Jan 20, 2008 at 03:16:25PM +1030, David Newall wrote:> >> Andi Kleen wrote:>> >>> On Sun, Jan 20, 2008 at 12:57:29PM +1030, David Newall wrote:>>> >>> >>>> compatibility. This is a sleeping giant for Linux. There are plenty of>>>> >>>> >>> Interesting choice of words.>>> >>> >> KFC and Dominoes use SCO for their cash registers, to pick just two>> enormous future opportunities.>> >> I suppose if they update their cash registers they will just go > with fully Linux binaries.>

It's not necessarily that simple. It might be for KFC and Dominoes, butfor others, SCO is not the complete story. Many legacy systems arewritten in COBOL, and must pay a per-seat licence for that on top of theper-seat licence for UNIX. It is these systems that are most attractedtowards SCO compatibility.

>>> But it does not make sense for all Linux kernels to always check for iBCS executables>>> when they don't have to code to run them anyways.>>> >>> >> I don't suppose you're suggesting this will make a big difference. Even>> if every exec did nothing but immediately exit, it still wouldn't make>> much difference.>> >> It's not a big difference, but why do unnecessary work on all > Linux kernels? There are a lot of Linux machines out there and > if all of them only do a little unnecessary work each fork()> over a year it adds up to really a lot of wasted cycles.>

It still adds up to something that nobody can perceive, not even using avery fine stopwatch and counting over a period of years.

> Especially since the few people who might really> need it can easily readd it.> No. Very few people can add it, easily or otherwise. Perhaps KFC couldemploy somebody to add it, but they'd more likely be able to converttheir entire software stack instead. The paint shops and mechanics ofthe world would have little chance of that.

> But Linux is not good for this currently, at least not unless you> add a significant patch (which I'm not sure does even exist> for modern 2.6; iBCS was mainly deployed on 2.4 kernels). And when you > add that patch you can easily readd the strcmps too.>

Yes, I agree. Neither side of this issue is of great moment. On theone hand we have something that's half-baked at best; on the other handwe want to remove it for non perceivable gain or benefit.

>> simplification of the story, I know, but still hits the plot highlights.>> >> You're worried about this patch generating headlines?

No, I don't see this as headline making material. The existing code,though, is a rough spot in the kernel. So long as it's there, somebodywill feel the need to scratch it, as you do. Absent the choice ofremoving the code, and the only way left to scratch is to complete it. Remove the code and there's nothing there that itches, which is a badthing in this case.